Lake Hancza

Hancza reaches 108.5 metres, which makes it the deepest lake in Poland and the deepest anywhere on the North European Plain - a subglacial trench melted under the ice and left as a narrow ribbon of water about four and a half kilometres long and at most 1.2 wide, some 311 hectares in all, with steep sides going straight down. The depth and the cold keep it exceptionally clear, and it is the best-known freshwater dive site in the country, with visibility that is good by Polish standards and a bottom of boulders and drop-offs; several dive operators work out of the villages on the shore. There is a relict fauna in it left over from colder conditions after the ice, including species otherwise found much further north. It sits inside the Suwalki Landscape Park, in a landscape of moraine hills that is one of the most sculpted in Poland, and the walk along the shore gives the shape of the trench better than a boat does.

Highlights

• 108.5 metres deep - the deepest lake in Poland and on the North European Plain.
• A subglacial trench - at most 1.2 kilometres wide with sides going straight down.
• A dive site - cold, clear water with boulder drop-offs and local operators.
• Moraine hills around it - inside the Suwalki Landscape Park.

When to go

June to September. Half a day, longer to dive.

Things to know

The water is very cold at depth all year and diving needs proper kit and a local operator. The shore is steep in places. Facilities are minimal. Winters here are the coldest in Poland.

Nearby

Suwalki Landscape Park surrounds it; Wigry is south-east.

Key facts